Supporting collaborative information sharing with the World-Wide Web:
The
BSCW Shared Workspace system

Richard Bentley, GMD FIT.CSCWThilo Horstmann, GMD FIT.CSCW

Abstract

The CSCW group at the German National Research Centre for Computer
Science (GMD FIT.CSCW) has been developing collaborative systems for
over 10 years. Since October 1994, the Basic Support for Cooperative
Work project (BSCW) has been investigating the suitability of the
World-Wide Web (W3) as an enabling technology, which can be extended
with flexible and lightweight mechanisms to support cooperative
work. Our efforts to date have yielded the BSCW Shared Workspace
system - an extended W3 server which provides basic facilities for
collaborative information sharing, activity awareness, and external
application integration across Macintosh, PC and Sun platforms [1].

The BSCW Shared Workspace system was conceived as an alternative
to tools which currently support collaborative working between
widely-dispersed participants, such as electronic mail and ftp. Such
systems are effective in supporting the exchange of
information, but provide little help for true information
sharing, where the context in which information is provided and
modified is supported and presented by the system to cooperating
users. As such, the BSCW shared workspace integrates the simple
facilities found in ftp - namely the storage and retrieval of
documents - with more sophisticated features such as member
administration, a check-in/out facility, access to meta-information
about documents and members, and a simple event service with which
users are kept informed, at-a-glance, of changes in the status of
information in the workspace. These facilities are provided by an
extended HTTP server [2], integrated with a simple object database,
and can be accessed using any standard W3 client on a number of
different platforms. Where additional client-side functionality is
required, (as is the case for example with local file browsers for
adding documents to a workspace), this has been realised as
client-specific 'helper applications'.

In the proposed presentation, we will describe and demonstrate the
design and implementation of the BSCW Shared Workspace system. For the
most part, this has involved extension of the NCSA HTTP daemon through
the standard CGI interface, but has also required some modification of
the server itself. We will describe these modifications, such as the
implementation of the PUT protocol to support document transmission to
a W3 server, and the extension of the logging facilities most servers
provide, and explain the need for such basic modifications when
considering the implementation of systems to support collaborative
work. Based on our experiences gained over the last year of working
with W3, we will also discuss the suitability of the stateless HTTP
protocol, the HTML mark-up language, and the general central-server W3
architectural model for realising collaborative applications. Finally
we will highlight some current trends in W3 development which
potentially address some of the current problems with W3 as a basis
for development of more powerful CSCW systems - most notably the
potential for client side execution and inter client communication
offered by the Java interpreter, already supported in Sun's HotJava
client and soon to be integrated with the Netscape navigator.

[1] The current version of the BSCW shared workspace system is
accessible over the Web. To use the system, complete the simple
registration form at http://levante.gmd.de:9000/registration_form.cgi,
which asks you to provide a user name, initial password and email
address. The server will then give instructions for accessing and
creating new workspaces. (For more information on the BSCW project,
the project page can be found at http://orgwis.gmd.de/ BSCW)

[2] The current version of the BSCW Shared Workspace system is an
extension of the NCSA HTTP 1.4.2 daemon